Bullet fired by armed gang misses Thornlie mum checking on her baby by just centimetres

An armed gang roaming Perth's south with a handgun has fired a shot in a Thornlie street, missing a mother checking on her child by just centimetres.

Emily Taylor was checking on her 14-month-old son when someone on Hulme Street pulled the trigger on a handgun.

The bullet burst through a window and then through an internal wall ending up next to Emily, who was standing in her home’s study.

“Obviously it was a little bit of a shock, you don't expect a bullet to come flying through your window,” Emily told 7NEWS.

SEE THE DAMAGE IN THE VIDEO PLAYER ABOVE.

The shot was fired about 1am but it wasn't until hours later that Emily and her husband realised they'd been caught in the crossfire and reported it to police.

Officers have since been and gone.

The bullet was taken away by forensics, with detectives now hunting a dangerous gang of men.

"There was a big loud pop and plaster came flying out the wall,” Emily said.

“We just thought we had a burst pipe until later this morning there was a gunshot whole through one of our windows so yeah, it's a bit scary."